RESUMO
In tropical and subtropical oceanic surface waters phosphate scarcity can limit microbial productivity. However, these environments also have bioavailable forms of phosphorus incorporated into dissolved organic matter (DOM) that microbes with the necessary transport and hydrolysis metabolic pathways can access to supplement their phosphorus requirements. In this study we evaluated how the environment shapes the abundance and taxonomic distribution of the bacterial carbon-phosphorus (C-P) lyase pathway, an enzyme complex evolved to extract phosphate from phosphonates. Phosphonates are organophosphorus compounds characterized by a highly stable C-P bond and are enriched in marine DOM. Similar to other known bacterial adaptions to low phosphate environments, C-P lyase was found to become more prevalent as phosphate concentrations decreased. C-P lyase was particularly enriched in the Mediterranean Sea and North Atlantic Ocean, two regions that feature sustained periods of phosphate depletion. In these regions, C-P lyase was prevalent in several lineages of Alphaproteobacteria (Pelagibacter, SAR116, Roseobacter and Rhodospirillales), Gammaproteobacteria, and Actinobacteria. The global scope of this analysis supports previous studies that infer phosphonate catabolism via C-P lyase is an important adaptive strategy implemented by bacteria to alleviate phosphate limitation and expands the known geographic extent and taxonomic affiliation of this metabolic pathway in the ocean.
Assuntos
Actinobacteria/metabolismo , Liases/metabolismo , Fosfatos/metabolismo , Proteobactérias/metabolismo , Roseobacter/metabolismo , Actinobacteria/classificação , Actinobacteria/genética , Actinobacteria/isolamento & purificação , Oceano Atlântico , Carbono/metabolismo , Liases/genética , Mar Mediterrâneo , Organofosfonatos/metabolismo , Compostos Organofosforados/metabolismo , Fosfatos/análise , Proteobactérias/classificação , Proteobactérias/genética , Proteobactérias/isolamento & purificação , Roseobacter/classificação , Roseobacter/genética , Roseobacter/isolamento & purificação , Água do Mar/análise , Água do Mar/microbiologiaRESUMO
The marine unicellular cyanobacterium Prochlorococcus is an abundant primary producer and widespread inhabitant of the photic layer in tropical and subtropical marine ecosystems, where the inorganic nutrients required for growth are limiting. In this study, we demonstrate that Prochlorococcus high-light strain MIT9301, an isolate from the phosphate-depleted subtropical North Atlantic Ocean, can oxidize methylphosphonate (MPn) and hydroxymethylphosphonate (HMPn), two phosphonate compounds present in marine dissolved organic matter, to obtain phosphorus. The oxidation of these phosphonates releases the methyl group as formate, which is both excreted and assimilated into purines in RNA and DNA. Genes encoding the predicted phosphonate oxidative pathway of MIT9301 were predominantly present in Prochlorococcus genomes from parts of the North Atlantic Ocean where phosphate availability is typically low, suggesting that phosphonate oxidation is an ecosystem-specific adaptation of some Prochlorococcus populations to cope with phosphate scarcity.IMPORTANCE Until recently, MPn was only known to be degraded in the environment by the bacterial carbon-phosphorus (CP) lyase pathway, a reaction that releases the greenhouse gas methane. The identification of a formate-yielding MPn oxidative pathway in the marine planctomycete Gimesia maris (S. R. Gama, M. Vogt, T. Kalina, K. Hupp, et al., ACS Chem Biol 14:735-741, 2019, https://doi.org/10.1021/acschembio.9b00024) and the presence of this pathway in Prochlorococcus indicate that this compound can follow an alternative fate in the environment while providing a valuable source of P to organisms. In the ocean, where MPn is a major component of dissolved organic matter, the oxidation of MPn to formate by Prochlorococcus may direct the flow of this one-carbon compound to carbon dioxide or assimilation into biomass, thus limiting the production of methane.
Assuntos
Carbono/metabolismo , Formiatos/metabolismo , Compostos Organofosforados/metabolismo , Fosfatos/metabolismo , Prochlorococcus/metabolismo , Purinas/metabolismo , OxirreduçãoRESUMO
Ruptured bronchial artery pseudoaneurysms with mediastinal hematoma are rare entities with a very limited number of published cases to date. The diagnosis of such cases can be difficult as the patient may present with symptoms mimicking other diseases, mainly mediastinal malignancy. A high degree of clinical suspicion and imaging techniques like contrast-enhanced computed tomography (CECT) chest and computed tomography angiography (CTA) aids in the diagnosis. Under the lights of an interventional radiologist, an urgent endovascular approach is most commonly preferred for its nonsurgical management. We present a rare case of a 47-year-old male with no previous lung disease or trauma with dyspnea and sudden onset chest pain. A massive effusion was suspected on the right side. CECT chest and digital subtraction angiography (DSA) revealed a pseudoaneurysm of a bronchial vessel with associated mediastinal hematoma, collapse of basal right lower lobe, and collection in right pleural space. This patient was later successfully treated by endovascular embolization techniques. Bronchial artery pseudoaneurysm may be considered a remote possibility in the absence of trauma or other lung diseases that may present with a massive hemothorax or mediastinal hematoma. Although CECT can be useful, digital angiography is considered the gold standard. Early intervention with the endovascular approach is a commonly recommended technique.
RESUMO
Diel oscillations in primary and secondary production, growth, metabolic activity, and gene expression commonly occur in marine microbial communities in ocean surface waters. Diel periodicity of gene transcription has been demonstrated in photoautotrophic and heterotrophic microbes in both coastal and open ocean environments. To better define the spatiotemporal distribution and patterns of these daily oscillations, we investigated how diel periodicity in gene transcripts changed with depth from the surface waters to the upper mesopelagic. We postulated that diel oscillation of transcript abundances would diminish at greater depths across the collective microbial community due to decreasing light availability. The results showed that the number and total proportion of gene transcripts and taxa exhibiting diel periodicity were greatest in the shallow sunlit mixed layer, diminished rapidly with increasing depth to the base of the euphotic zone, and could not be detected in the mesopelagic. The results confirmed an overall decrease in microbial diel transcript oscillation with depth through the euphotic zone and suggested a relationship between abundance of diel oscillating transcripts and the daily integrated light exposure experienced by planktonic microbes in the water column. Local dissolved macronutrient concentration also appeared to influence the diel transcriptional patterns of specific microbial genes. The diminishing diel transcript oscillations found at increasing depths suggest that diel patterns of other microbial processes and interactions may likewise be attenuated at depth.
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Semi-labile dissolved organic matter (DOM) accumulates in surface waters of the oligotrophic ocean gyres and turns over on seasonal to annual timescales. This reservoir of DOM represents an important source of carbon, energy, and nutrients to marine microbial communities but the identity of the microorganisms and the biochemical pathways underlying the cycling of DOM remain largely uncharacterized. In this study we describe bacteria isolated from the North Pacific Subtropical Gyre (NPSG) near Hawaii that are able to degrade phosphonates associated with high molecular weight dissolved organic matter (HMWDOM), which represents a large fraction of semi-labile DOM. We amended dilution-to-extinction cultures with HMWDOM collected from NPSG surface waters and with purified HMWDOM enriched with polysaccharides bearing alkylphosphonate esters. The HMWDOM-amended cultures were enriched in Roseobacter isolates closely related to Sulfitobacter and close relatives of hydrocarbon-degrading bacteria of the Oceanospirillaceae family, many of which encoded phosphonate degradation pathways. Sulfitobacter cultures encoding C-P lyase were able to catabolize methylphosphonate and 2-hydroxyethylphosphonate, as well as the esters of these phosphonates found in native HMWDOM polysaccharides to acquire phosphorus while producing methane and ethylene, respectively. Conversely, growth of these isolates on HMWDOM polysaccharides as carbon source did not support robust increases in cell yields, suggesting that the constituent carbohydrates in HMWDOM were not readily available to these individual isolates. We postulate that the complete remineralization of HMWDOM polysaccharides requires more complex microbial inter-species interactions. The degradation of phosphonate esters and other common substitutions in marine polysaccharides may be key steps in the turnover of marine DOM.
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The members of the OM43 clade of Betaproteobacteria are abundant coastal methylotrophs with a range of carbon-utilizing capabilities. However, their underlying transcriptional and metabolic responses to shifting conditions or different carbon substrates remain poorly understood. We examined the transcriptional dynamics of OM43 isolate NB0046 subjected to various inorganic nutrient, vitamin, and carbon substrate regimes over different growth phases to (i) develop a quantitative model of its mRNA content; (ii) identify transcriptional markers of physiological activity, nutritional state, and carbon and energy utilization; and (iii) identify pathways involved in methanol or naturally occurring dissolved organic matter (DOM) metabolism. Quantitative transcriptomics, achieved through addition of internal RNA standards, allowed for analyses on a transcripts-per-cell scale. This streamlined bacterium exhibited substantial shifts in total mRNA content (ranging from 1,800 to 17 transcripts cell-1 in the exponential and deep stationary phases, respectively) and gene-specific transcript abundances (>1,000-fold increases in some cases), depending on the growth phase and nutrient conditions. Carbon metabolism genes exhibited substantial dynamics, including those for ribulose monophosphate, tricarboxylic acid (TCA), and proteorhodopsin, as well as methanol dehydrogenase (xoxF), which, while always the most abundant transcript, increased from 5 to 120 transcripts cell-1 when cultures were nutrient and vitamin amended. In the DOM treatment, upregulation of TCA cycle, methylcitrate cycle, vitamin, and organic phosphorus genes suggested a metabolic route for this complex mixture of carbon substrates. The genome-wide inventory of transcript abundances produced here provides insight into a streamlined marine bacterium's regulation of carbon metabolism and energy flow, providing benchmarks for evaluating the activity of OM43 populations in situ IMPORTANCE: Bacteria exert a substantial influence on marine organic matter flux, yet the carbon components targeted by specific bacterial groups, as well as how those groups' metabolic activities change under different conditions, are not well understood. Gene expression studies of model organisms can identify these responses under defined conditions, which can then be compared to environmental transcriptomes to elucidate in situ activities. This integration, however, is limited by the data's relative nature. Here, we report the fully quantitative transcriptome of a marine bacterium, providing a genome-wide survey of cellular transcript abundances and how they change with different states of growth, nutrient conditions, and carbon substrates. The results revealed the dynamic metabolic strategies this methylotroph has for processing both simple one-carbon compounds and the complex multicarbon substrates of naturally derived marine organic matter and provide baseline quantitative data for identifying their in situ activities and impact on the marine carbon cycle.
Assuntos
Organismos Aquáticos/efeitos dos fármacos , Organismos Aquáticos/crescimento & desenvolvimento , Betaproteobacteria/efeitos dos fármacos , Betaproteobacteria/crescimento & desenvolvimento , Carbono/metabolismo , Perfilação da Expressão Gênica , Compostos Orgânicos/metabolismo , Redes e Vias MetabólicasRESUMO
The role of bacterioplankton in the cycling of marine dissolved organic matter (DOM) is central to the carbon and energy balance in the ocean, yet there are few model organisms available to investigate the genes, metabolic pathways, and biochemical mechanisms involved in the degradation of this globally important carbon pool. To obtain microbial isolates capable of degrading semi-labile DOM for growth, we conducted dilution to extinction cultivation experiments using seawater enriched with high molecular weight (HMW) DOM. In total, 93 isolates were obtained. Amendments using HMW DOM to increase the dissolved organic carbon concentration 4x (280 µM) or 10x (700 µM) the ocean surface water concentrations yielded positive growth in 4-6% of replicate dilutions, whereas <1% scored positive for growth in non-DOM-amended controls. The majority (71%) of isolates displayed a distinct increase in cell yields when grown in increasing concentrations of HMW DOM. Whole-genome sequencing was used to screen the culture collection for purity and to determine the phylogenetic identity of the isolates. Eleven percent of the isolates belonged to the gammaproteobacteria including Alteromonadales (the SAR92 clade) and Vibrio. Surprisingly, 85% of isolates belonged to the methylotrophic OM43 clade of betaproteobacteria, bacteria thought to metabolically specialize in degrading C1 compounds. Growth of these isolates on methanol confirmed their methylotrophic phenotype. Our results indicate that dilution to extinction cultivation enriched with natural sources of organic substrates has a potential to reveal the previously unsuspected relationships between naturally occurring organic nutrients and the microorganisms that consume them.
Assuntos
Bactérias/metabolismo , Metanol/metabolismo , Compostos Orgânicos/metabolismo , Água do Mar/microbiologia , Processos Autotróficos , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Carbono/metabolismo , Meios de Cultura/química , Meios de Cultura/metabolismo , Dados de Sequência Molecular , Peso Molecular , Compostos Orgânicos/química , Filogenia , Água do Mar/químicaRESUMO
RESUMEN Introducción: la fragilidad es un deterioro progresivo de los sistemas fisiológicos, relacionado con la edad, que disminuye las reservas de capacidad intrínseca, lo que confiere mayor vulnerabilidad a factores de estrés. Si bien tiende a empeorar espontáneamente, con intervenciones adecuadas y precoces se pueden revertir, enlentecer o aminorar sus consecuencias. Objetivos: determinar la frecuencia de fragilidad del adulto mayor según los criterios de Fried en tres Unidades de Salud Familiar de Areguá, Paraguay, en 2019. Metodología: estudio observacional, descriptivo, prospectivo, multicéntrico. Se incluyeron varones y mujeres ≥60 años asistidos en las Unidades de Salud Familiar de Yuquyty, Costa Fleytas y Caacupemí (Areguá, Paraguay) en 2019. Se midieron variables antropométricas y clínicas. La fragilidad se determinó con el cuestionario de Fried, previo consentimiento informado. Resultados: se incluyeron 81 sujetos, con edad media 71±7 años, con predominio del sexo femenino (65%). Las comorbilidades más frecuentes fueron la hipertensión arterial, artropatías y diabetes mellitus. La depresión fue autorreportada en 9,8%. Se detectó fragilidad en 53%. El déficit más frecuente de los criterios de Fried fue la lentitud en la marcha. El factor de riesgo asociado a la fragilidad fue el sexo femenino (p 0,006). Conclusiones: la fragilidad se detectó en 53%, con predominio en el sexo femenino.
ABSTRACT Introduction: Frailty is a progressive deterioration of physiological systems, related to age, which reduces the reserves of intrinsic capacity, which confers greater vulnerability to stressors. Although it tends to worsen spontaneously, with appropriate and early interventions, its consequences can be reversed, slowed or reduced. Objectives: To determine the frequency of frailty of the elderly according to Fried criteria in three Family Health Units of Areguá, Paraguay, in 2019. Methodology: Observational, descriptive, prospective, multicenter study. Men and women aged ≥60 years who attended the Family Health Units of Yuquyty, Costa Fleytas and Caacupemí (Areguá, Paraguay) in 2019 were included. Anthropometric and clinical variables were measured. Frailty was determined with Fried questionnaire, after informed consent. Results: Eighty-one subjects were included, with a mean age of 71±7 years, with a predominance of women (65%). The most frequent comorbidities were high blood pressure, arthropathies, and diabetes mellitus. Depression was self-reported in 9.8%. Frailty was detected in 53% and the most frequent deficit in Fried criteria was slow gait. The risk factor associated with frailty was female sex (p=0.006). Conclusions: Frailty was detected in 53%, with a predominance of women.
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The type VI secretion system (T6SS) mediates protein translocation across the cell membrane of Gram-negative bacteria, including Vibrio cholerae - the causative agent of cholera. All V. cholerae strains examined to date harbor gene clusters encoding a T6SS. Structural similarity and sequence homology between components of the T6SS and the T4 bacteriophage cell-puncturing device suggest that the T6SS functions as a contractile molecular syringe to inject effector molecules into prokaryotic and eukaryotic target cells. Regulation of the T6SS is critical. A subset of V. cholerae strains, including the clinical O37 serogroup strain V52, express T6SS constitutively. In contrast, pandemic strains impose tight control that can be genetically disrupted: mutations in the quorum sensing gene luxO and the newly described regulator gene tsrA lead to constitutive T6SS expression in the El Tor strain C6706. In this report, we examined environmental V. cholerae isolates from the Rio Grande with regard to T6SS regulation. Rough V. cholerae lacking O-antigen carried a nonsense mutation in the gene encoding the global T6SS regulator VasH and did not display virulent behavior towards Escherichia coli and other environmental bacteria. In contrast, smooth V. cholerae strains engaged constitutively in type VI-mediated secretion and displayed virulence towards prokaryotes (E. coli and other environmental bacteria) and a eukaryote (the social amoeba Dictyostelium discoideum). Furthermore, smooth V. cholerae strains were able to outcompete each other in a T6SS-dependent manner. The work presented here suggests that constitutive T6SS expression provides V. cholerae with an advantage in intraspecific and interspecific competition.
Assuntos
Sistemas de Secreção Bacterianos/fisiologia , Vibrio cholerae/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Sistemas de Secreção Bacterianos/genética , Regulação Bacteriana da Expressão Gênica/genética , Regulação Bacteriana da Expressão Gênica/fisiologia , Vibrio cholerae/genética , Vibrio cholerae/fisiologiaRESUMO
We have evaluated the induction of the flocculent phenotype of Kloeckera apiculata by glucose mc1 and propose a pathway involved in carbohydrate flocculation induction. Pulses of glucose were given to cells growing in glucose-poor medium (2 g l(-1)) and the flocculation percentage was measured. To elucidate the mechanism involved in flocculation induction, cycloheximide was injected into the cultures 120 min before the glucose pulse. 2,4-Dinitrophenol or cAMP was added to the media instead, or simultaneously with glucose, while a protein kinase A (PKA) inhibitor was added 30 min before the glucose pulse. With 20 and 50 g l(-1) glucose pulse, the yeast flocculation percentage arises to 55 and 65%, respectively. The quantity of proteins and the reflocculating capacity of a lectinic protein extract from the yeast cell wall increase as the concentration of glucose pulse was higher. Cycloheximide prevented the glucose-induced flocculation, while cAMP or 2,4-dinitrophenol increased it 4- and 5-fold, respectively. PKA inhibitor completely prevented the glucose induction flocculation. The flocculent phenotype of K. apiculata mc1 was induced by glucose and the mechanism seems to imply de novo protein (lectin) synthesis via the PKA transduction pathway. This work contributes to the elucidation of the mechanism involved in flocculation induction by glucose of a non-Saccharomyces wine yeast, K. apiculata, which has not been reported. The induction of flocculation by glucose could be a biotechnological tool for the early removal of the indigenous microorganisms from the grape must before the inoculation of a selected starter strain to conduct the alcohol fermentation.
Assuntos
Adesão Celular , Glucose/metabolismo , Saccharomycetales/metabolismo , Saccharomycetales/fisiologia , 2,4-Dinitrofenol/farmacologia , AMP Cíclico/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/antagonistas & inibidores , Cicloeximida/farmacologia , Floculação , Proteínas Fúngicas/metabolismo , Lectinas/metabolismo , Inibidores de Proteínas Quinases/farmacologia , Inibidores da Síntese de Proteínas/farmacologia , Saccharomycetales/efeitos dos fármacos , Desacopladores/farmacologiaRESUMO
Se realizó un estudio descriptivo dirigido a determinar la incidencia acumulada de los factores de riesgo cardiovasculares enpacientes ingresados en el departamento de Medicina Interna del Hospital Roosevelt durante el período de febrero a octubre delaño 2010, incluyendo en el estudio a un total de 177 pacientes. Tomando como sujeto de estudio los factores de riesgocardiovascular: diabetes mellitus, hipertensión, circunferencia abdominal, tabaquismo, alcoholismo, actividad física, sexo y perfillipídico, en los pacientes mayores de 65 años. El objetivo principal fué la caracterización epidemiológica de los factores deriesgo cardiovascular en pacientes mayores de 65 años y formar una base de datos epidemiológica. De los 177 pacientesestudiados el 50% fueron hombres, encontrando un 47% con antecedentes de Diabetes Mellitus, así como un 62% de pacienteshipertensos. También se evidenció que un 42% de los pacientes se encontraban dentro del rango normal de índice de masacorporal y que la mayoría de pacientes estaban en sobrepeso y obesidad con un total del 49%. Casi la mitad de los pacientespresentaron cifras de glicemia al azar alteradas, pero solamente un 27% de los pacientes presentaron hipercolesterolemia. El68% de pacientes no presentaba antecedente de tabaquismo y el uso previo de alcohol. Un total de 133 pacientes no realizabanningún tipo de actividad física. Concluyendo así que los principales factores de riesgo que afectaron a los pacientes evaluadosfueron la hipertensión arterial, el sedentarismo, el sobrepeso y obesidad.
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Humanos , Doenças Cardiovasculares/complicações , Doenças Cardiovasculares/diagnóstico , Fatores de RiscoRESUMO
Se presenta un caso clínico de mordida abierta esqueletal en paciente adulto. Se extraen los primeros premolares superiores e inferiores y se logra con aparatología fija y técnica combinada el contacto anterior